A researcher selects a random sample of 200 students to determine whether there is a relationship between the number of days a student is absent and the student's grade point average. The
correlation coefficient, r, of the data is -0.765. On the basis of the correlation coefficient alone, can the
researcher conclude that an increase in the number of days a student is absent causes the student's
grades to drop?
No, because other factors may have influenced the student grades.
Yes, because ris very close to -1.
No, because ris negative.
Yes, because the students in the sample were randomly selected.
no

a. is correct

- "runner b is moving at a slower rate."

- "the graphs shown are graphs of distance(km) against time(min).

the slopes of this graphs are are given by:

slope = (change in y)/(change in x)

= (change in distance)/(change in time)

this is the formula for finding the speed. so, the slope of these graphs represent the speed of the runner.

taking each division in the graph to represent 1 on both axis:

runner a ⇒ speed = (2-0)/(1-0)

= 2/1

= 2 km/min

runner b ⇒ speed = (3-0)/(3-0)

= 3/3

= 1 km/min

this shows that   runner b is moving at a slower rate."

step-by-step explanation:

step 1: solve one of the equations for one of the variables. let's solve the first equation for y:

step 2: substitute that equation into the other equation, and solve for x.

step 3: substitute x = 4 x = 4 x=4 into one of the original equations, and solve for y.